In general, such container tanks are constructed to ISO standards and comprise a pair of transversely mounted end frames with a tank mounted between the end frames. In general, the tank has a central shell of either circular, elliptical or ovoid cross section closed by end caps. The end caps, in general, are dished and are convex when viewed externally. The end frames, in general, comprise a pair of upstanding spaced apart side members joined by top and bottom cross members, the side, top and bottom members in general terminate in corner castings which are constructed to ISO standards and in general comprise openings to facilitate handling and stacking of the container tanks. Inclined connecting members extending between the side and top and bottom members adjacent the corners of the end frames are provided for mounting the tank to the end frames. Bearer members extend from the tank to the end frames for mounting the tank to the end frames. In general, four bearer members are provided extending from each end of the tank to engage the adjacent end frame. The bearer members, in general, are provided at positions of 45.degree. intermediate a central horizontal and central vertical plane of the tank.
A typical construction of container tank which comprises a pair of end frames and a tank mounted to the end frame by bearer members is described and illustrated in British Patent Application Specification No. 2,168,415A.
While such container tanks, in general, are adequate for the transportation of bulk materials or liquids, they tend to be relatively heavy and thus transportation and handling of such container tanks tends to be relatively inefficient. By virtue of the construction of these container tanks, the tank acts as an integral part of the structure, and furthermore, the bearer members are structural members of the container tank. Because of this, the bearer members must be of sufficient size and construction to carry the loads to which they are subjected. Thus, in general, the bearer members of such tanks are of relatively robust construction and large cross sectional area. This, needless to say, adds significantly to the weight of the container tank, which thus leads to inefficiencies in the transportation and handling of such container tanks.